A case report is presented in which a radiolucentarea in the anterior portion of the mandible was diagnosed clinically as an apical cyst. However, when examined microscopically, it was discovered to be a cystic ameloblastoma. Cystic ameloblastoma is described as a distinctvariant of ameloblastoma in which the response to curettage is favorable with a low recurrence rate. In many cases, it may imitate an endodontic apical lesion, and be mistreated. The importance of precise diagnosis by the endodontist and the treatment recommended in such cases are discussed.